At 5:28 PM +1000 7/22/03, Alan Gray wrote:
I've had the same problems finding the 4937 tuner, and am currently in
the process of adapting the hardware design to use a 4702 tuner module
with an IF output at 36MHz. When we contacted Microtune they suggested
using a tuner such as the 4702 and an additional downconversion stage
(they suggested the NEC Electronics UPC2798GR which is apparently what
they use in the 4937 tuners anyway)
I've ordered a few of the NEC IC's but they're taking a long time to
arrive. In the mean time I'm going to attempt to put together some
hardware to use a 4702 module as is. I'm hoping that I should be able to
sample the bandlimited signal without any downconversion (it's
theoretically possible) and thus avoid the need for any more components.
I've been shying away from Microtune since they and their manufacturers
rep for my area have been so difficult to work with. They sent me a sample
of the 4937 and swore up and down they still had them in stock (in the
Philippines) but for the life of me I could not get them to send me an
official quote. I was all set to buy $1000 of tuners (their minimum
order) and told them the PO would be cut as soon as I got a quote, but
they don't seem to be interested in my business. (I tried for weeks to get
a quote.) Given this experience, I am reluctant to jump to another
Microtune product. If you're willing to do an external downconversion
from 36-44 MHz, it seems to me that there are a lot of tuners available to
consider... I've been looking at the Zarlink chips... Anyone else have any
good candidates?